Nits to readme.
Nits to readme.

columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,columbia/xtern,hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,hemingcui/xtern_with_paxos